1. Field of the Invention
The present invention relates to an ink-jet printer that ejects, from nozzles thereof, droplets of ink and thereby records an image on a recording medium, and particularly to such an ink-jet printer that can remove air bubbles produced in one or more ink-flow passages and thereby maintain a high recording quality. The present invention also relates to a method of sucking ink that has been discharged into an air-discharge cap of an ink-jet printer when air bubbles are removed through the cap, the ink-jet printer additionally including one or more ink ejection portions (or one or more recording heads) that eject, from nozzles thereof, droplets of ink, and one or more ink-flow passages which supply the ink to the ink-ejection portions and in which air bubbles are produced or separated from the ink.
2. Discussion of Related Art
There has been proposed an ink-jet printer including a housing, a plurality of ink ejection portions each of which ejects, from nozzles thereof, droplets of ink, a carriage that carries the ink ejection portions and is movable relative to the housing, a plurality of ink tanks that store different sorts of inks to be supplied to the ink ejection portions, and a plurality of ink flow passages that supply the different sorts of inks from the ink tanks to the ink ejection portions. In the case where the ink tanks store respective sorts of inks having different colors and the ink ejection portions eject droplets of those inks supplied from the ink tanks via the ink flow passages, the ink-jet printer can record a full-color image.
For example, Japanese Patent Application Publication No. 2005-246928 discloses an ink-jet printer including a carriage, a plurality of ink flow passages, a plurality of air-bubble collecting chambers which are provided on the carriage and each of which collects air bubbles produced in a corresponding one of the ink flow passages, a plurality of discharging passages that are provided on the carriage and communicate with the air-bubble collecting chambers, respectively, a plurality of normally-closed opening and closing valves that are respectively provided in the discharging passages, a housing, a plurality of bar-like opening and closing members which are supported by the housing and each of which opens and closes a corresponding one of the opening and closing valves, and an air-discharge cap which is supported by the housing, through which the opening and closing members slideably extend, and which can be closely contacted with the carriage so as to cover respective outlets of the discharging passages and define an air-tight space communicating with the outlets.
In the above-indicated ink-jet printer, the air bubbles produced in the ink flow passages are temporarily collected by the air-bubble collecting chambers and, when the opening and closing valves are opened by the opening and closing members, the air bubbles are discharged into the air-tight space defined by the air-discharge cap. Thus, the air bubbles produced in the ink flow passages can be efficiently removed and accordingly a high recording quality of the ink-jet printer can be maintained. In addition, since the air bubbles collected by the air-bubble collecting chambers are not directly discharged into the atmosphere but are discharged into the air-tight space defined by the air-discharge cap, the ambient air can be prevented from entering the air-bubble collecting chambers. Therefore, the air bubbles produced in the ink flow passages can be more efficiently removed from the ink-jet printer.
When the air bubbles are removed in the above-described manner, respective certain amounts of inks present in the ink flow passages are discharged with the air bubbles into the air-discharge cap. Hence, the above-indicated application publication proposes to apply, after the removal of the air bubbles, suction to the air-discharge cap so as to suck and remove the inks present in the cap.
However, ink has a certain degree of viscosity and accordingly the ink adhered to the air-discharge cap may not be removed by just applying suction thereto.
In addition, the definition or formation of the air-tight space needs to dispose the air-discharge cap such that the cap is movable relative to the carriage and also needs to apply a biasing force to move the cap toward the carriage. In this case, since the air-discharge cap can be brought into pressed contact with the carriage, the cap can be moved away from the carriage against the biasing force, and the air tightness of the air-tight space can be assured at a high reliability.
However, the arrangement needed to support, with a frame-side member (or a housing), the air-discharge cap such that the cap is movable against the biasing force may be complicated and/or increased in size.